In a known device the rotor lid is attached to a swiveling cover which covers the spinning station so that the rotor lid follows the movement of the cover (DE 25 32 637 A1). The cover is however supported below the opener device which precedes the spinning rotor so that the rotor lid carries out a sliding movement at the interface between the opener device housing and the fiber feeding channel, so that a seal provided at this location is subjected to heavy wear.